A fluorinated olefin/vinyl alcohol copolymer, i.e. a copolymer of a fluorinated olefin and vinyl alcohol, is used as a raw material for coating resins, a material for gas/liquid separation membranes, a gas barrier material, a sealing material for solar cells, a material for various surface protective sheets, a hydrophilic porous material, etc. (Patent Documents 1 and 2). As a method for producing a fluorinated olefin/vinyl alcohol copolymer, a method has already been known wherein a fluorinated olefin and vinyl acetate are copolymerized, followed by hydrolysis under an acidic or basic condition (Patent Documents 1 and 2, and Non-Patent Document 3).